Bilateral renal mass lesions.

A 28-year-old female presented with new-onset hypertension (blood pressure 160/98mmHg). Her physical examination was unremarkable, except pale conjunctiva. Laboratory studies showed haemoglobin 8.5 g/dl, leukocytes 25 800/mm, platelets 791 000/mm, serum creatinine 150 mmol/l and urea 5.8mmol/l. Urinalysis revealed numerous leukocytes. The abdominal ultrasound showed bilateral heterogeneous renal masses without hydronephrosis. The computed tomography of the abdomen is shown in Figure 1. Infiltrative kidney disease was diagnosed tentatively. Survey for tumour marker and bone marrow aspiration showed no evidence of malignancy. Renal biopsy revealed diffuse neutrophil infiltration of the interstitium and renal tubules with microabscess formation. Stains for Michaelis–Gutmann bodies (malacoplakia) were negative. Urine cultures grew Escherichia coli. After antibiotic treatment with ciprofloxacin 500mg twice a day for 3 months, the bilateral renal masses regressed markedly along with resolution of renal function and hypertension. Bilateral renal mass lesion is usually associated with haematological malignancies, infiltrative diseases, metastases, congenital or acquired renal cysts, malacoplakia and xanthogranulomatous pyelonephritis [1]. Acute bilateral non-obstructive pyelonephritis presenting with bilateral renal mass lesions but